The present invention relates to providing access to electric power, communications, and computer data services in a concrete floor of an office building, and more particularly, to providing user access to such services from a below floor slab distribution system by recessed and flush service activations.
Occupants of a modern office building generally require electric power, communication, and computer data services in various combinations, at a number of locations. Services are provided to the required locations by service distribution systems that are generally partially or entirely disposed within a concrete floor.
In-floor service distribution systems, such as ducts or cellular deck are cast into a concrete floor slab and require a relatively large initial investment at the time of construction. In addition, the capacity of such distribution systems must be determined before construction of the floor. The designed capacity may turn out not to be needed or may eventually be insufficient.
A distribution system that is assembled below the concrete slab and supporting deck sheet of a conventional concrete floor is independent of the floor, and can be expanded as needs arise. A conventional below floor slab system extends into the floor only through holes at which connection to the distribution system is required. These holes may be formed by opening core presets cast into the floor, or by boring through the concrete floor.
Activations, (including connectors connected to the distribution system or passages for routing conductors from the distribution system to locations above the floor, or both) provide access to service distribution systems. In-floor activations are assembled in activation presets in the floor through an opening in the floor surface. Activation presets are conventionally cast into the concrete slab overlying an in-floor distribution system providing a chamber within which connectors and other hardware may be assembled.
Floor fittings are activations that are positioned on the floor surface and are connected to a distribution system through holes extending to a distribution system in the floor or through the floor to a below floor slab distribution system. Floor fittings are most commonly used with below floor slab distribution systems and less commonly with in-floor distribution systems. Floor fitting activations have conventionally offered fewer activation configurations and fewer connections than in floor activations. Larger floor fittings now offer a larger number of connections, but occupy a larger area on the floor than conventional floor fittings.
Flush poke-through are activations that position connectors generally within the plane of the floor surface in a hole that extends into the concrete floor slab. Flush poke-throughs are generally positioned in holes bored into the floor and provide a small number of connections.
Presets are void forming structures that are cast into concrete floor slabs to provide access to distribution systems. A preset typically defines a chamber and has an opening at its upper end which is disposed close below the floor surface. A preset cap is placed over the preset to prevent concrete from filling the preset when the floor slab is being poured. Service distribution systems are conventionally accessed at a preset by removing (breaking away) the concrete overlying the preset cap.
Core presets are used to provide access to a single duct, raceway, or a below floor slab distribution system. In the case of a core preset overlying an in-floor distribution system, the core insert conventionally includes a service insert extending toward the floor surface from a duct or cell and to which a floor fitting can be secured. In the case of a core preset extending through a floor for connection to a below floor slab distribution system, the entire core present is removed leaving a hole into which a "poke-through" is positioned. A floor fitting is then secured to the poke-through.
Conventional activation presets overlie more than one raceway cell or duct of an in-floor distribution system. Activation presets are sized and constructed to accept an activation kit including connectors, shields, and other activation hardware. Typically, any one of a number of different activation kits may be installed in an activation preset to provide several possible connection configurations for the services.
Connection of a floor fitting to a distribution system requires one or more holes through which conductors are routed from the distribution system to the floor fitting. These holes are conventionally formed by either a core preset or boring a hole to an in-floor system, or, through the floor. Boring a hole in the floor to a distribution system is time-consuming, messy, and more expensive than removal of an insert preset. In the case of a below floor slab system, extending the distribution system, pulling connectors through the distribution system to the hole, and installing the poke-through are relatively expensive compared to installation of an activation kit in a service insert and pulling connectors from an in-floor system.
Floor fittings conventionally provide limited options for access to more than one service. A multi-service floor fitting and a poke-through having shields that separate conductors for different services provide activation of more than one service from a below floor slab distribution system through a single hole. A small number of connections to each service are provided, as compared to a multi-service preset activations utilized in in-floor systems. If more connections are required than can be provided by a single hole, separate single service poke-throughs and floor fittings are generally used. Multiple holes and service inserts are conventionally required for floor fittings to provide access to multiple services distributed by in-floor systems. Less commonly, a floor fitting may be mounted to a present overlying more than one duct or cell to provide connections to multiple services.
In addition to service and installation considerations, building fire codes affect construction of and connection to service distribution systems. Office building floors (including those in which service distribution systems and activations are installed), must prevent smoke, flame, and heat from spreading through the floor, that is, from one side of the floor to the other, for the period of time specified by building codes. Office building floors are typically an assembly including a metal deck sheet and an overlying concrete slab. A sufficiently thick concrete slab may be provided to achieve the required fire resistance. When the concrete does not provide the required fire resistance, the floor assembly may include insulation sprayed onto the underside of the metal deck sheet to increase the fire resistance of the floor assembly.
Service distribution systems and activations must be compatible with the floor's fire-proofing as well as the floor's structure and must maintain the required fire resistance. The various service distribution systems and activations differently affect the fire resistance of floor assemblies. In-floor distribution systems decrease the amount of concrete in the slab and provide metal heat conduction paths through the distribution system and presets from a location at or near the deck sheet to the upper surface of the floor. Floor assemblies having in-floor service distribution systems, particularly cellular raceway, conventionally require a greater amount of sprayed-on insulation to satisfy fire resistance requirements than solid concrete floors. The cost of an in-floor distribution system includes the cost of this additional insulation.
A below floor slab service distribution system is generally not part of the floor and consequently affects the fire resistance of the floor only at locations at which services are routed through the floor from the below floor slab distribution system. A below floor slab distribution system may be constructed after construction of the floor assembly in the space below the floor (and often above the dropped ceiling of the next lower floor). Consequently, the number of services and the number and location of connections to the services are selected after construction.
Connection to a below floor slab distribution system requires that holes be made through the floors compromising the fire resistance of the floor assembly. Poke-throughs have fire-resistance components that surround the conductors extending through the hole and restore the fire resistance of the floor.
Floors overlying below floor slab service distribution systems are conventionally constructed to achieve the required fire resistance without regard to the service distribution system. Core presets providing access to below floor slab distribution systems are made of materials, filled with materials that do not conduct heat well, or both and do not compromise the fire resistance of the floor assembly. Therefore, no additional floor fire-proofing is required as a result of the presence of these core presets. However, removal of core presets requires installation of fire resistance components, such as poke-throughs, with the service activation, increasing the cost of providing service activation.
Accordingly, a need exists for an activation for below floor slab service distribution system that provides more connections than conventional floor fittings, does not require a large fitting extending from the floor surface, allows connection to multiple services, and retains the benefits of low cost at time of construction. In addition, a need exists for an activation for a below floor slab distribution system: that provides connectors and routes for conductors for more than one service while maintaining the necessary separation of services; that allows connectors to be positioned flush with the floor surface or recessed in a void in the floor; and that provides increased access to below floor slab service distribution systems while not increasing the fire protection measures required to satisfy building codes.